All right, so having talked about
the heart sounds s1, s2, s3, s4,
let's talk about systole and really focus
on murmurs that occur during systole now
Whenever we describe our murmur, there's
going to be a few features that will come up
every time we talk about one.
And I have a little mnemonic
that I use called LISP-T.
It's not for everybody, but it works for me.
The L stands for location.
Where is the murmur located?
I is for intensity.
Another way of saying that is the grade of the
murmur and this is rated basically from 1 to a 6.
A 1 out of 6 murmur is very subtle.
You can put the stethoscope on the chest and
you really have to be in the right location.
The room has to be quiet and it has to be just
you're able to really focus and pay attention to
what you're hearing to catch a 1 out of 6 murmur.
A 2 out of 6 murmur's the more typical murmur
that you're going to pick up and that your
average medical student is going to pick up with you.
3 out of 6 murmur and a 4 out of
6 murmur are increasingly loud
up to the point where a 5 out of
6 murmur, you could hear with only
an edge of your stethoscope on the chest.
And a six, allegedly, you could hear with your
stethoscope even hovering above the chest.
So those are the intensity of the murmur.
S is the shape of the murmur.
Again, my LISP-T acronym, S is the shape and what
we're describing there is essentially the contour,
whether it's ascending and descending in
amplitude or simply strictly descending,
or if it's holosystolic, that is, it's
the same amplitude throughout systole.
And then the next part is P.
P is for the pitch.
As we've already talked about a little bit,
some murmurs or some sounds are lower in pitch
and some are higher in pitch,
so we'll be listening to that.
And then lastly, is the timing, when is it occurring?
Obviously, we want to know if it's
occurring in systole or diastole,
but we'd also want to know if it's early
in systole, late in diastole, etcetera.
So those are different features that we'll be
attending to as we move through these murmurs.
First up, the murmur of aortic stenosis.
So aortic stenosis, it's a problem with the
aortic valve o you might presume then that the
aortic area would be the most likely
place to hear an aortic stenosis murmur.
And while that's generally true,
the aortic stenosis murmur,
amongst all the other murmurs,
has a tendency to migrate.
So actually, the aortic stenosis murmur may
be heard all the way across the precordium,
even down here to the apex in
sort of a sash-like pattern.
So just because you hear the murmur best all the way
over here does not mean it's not aortic stenosis.
So that's the location.
An important feature about aortic stenosis murmur
is that the intensity does not really help us
to discern the severity of somebody's aortic
stenosis murmur or aortic stenosis disease.
Some patients may have a very subtle
soft murmur, maybe a 1 or 2 out of 6,
but they could actually have
severe critical aortic stenosis,
so it's not a great guide for this particular murmur.
Next up would be the shape, and the pitch.
So the classic description for the aortic stenosis
murmur is a so-called crescendo-decrescendo murmur
and you know, cardiologists for many,
many years have tried to use onomatopoeia,
which is a way of trying to come
up with a name to describe a sound
by making that sound with your mouth to describe
certain murmurs like before when I said,
"lub-dub" and "buh-lub-dub" and "lub-dee-bub",
those are, that's basically onomatopoeia.
The same thing applies with heart murmurs.
So the classic way to attempt to recreate
the sound or the murmur of your stenosis,
it's described as a coarse, harsh
sound like you're clearing your throat.
So it might sound something like this:
(crescendo-decrescendo aortic murmur sound)
And you can hear it as a crescendo-decrescendo
quality to the sound that I'm trying to recreate.
It's a mixture of high and low pitched
sounds, and I'll just do it again.
You're going to hear it anywhere in this area.
(crescendo-decrescendo aortic murmur sound)
Lastly, in terms of the timing, a
systolic murmur of aortic stenosis
can be either early, mid or in late systole.
In theory, the lateness of the
aortic stenosis murmur does
to some extent correlate with
the severity of aortic stenosis.
I can confess that I oftentimes can't
distinguish if a murmur is early or late systole,
but that doesn't mean that you shouldn't try.
The second thing is that many
murmurs radiate to other locations.
And in this case, since we're talking about
blood shooting out of the aortic outflow tract
and up into the carotids, we ought to be
able to hear this murmur up in the carotids.
So when I think somebody has
an aortic stenosis murmur,
I listen with my diaphragm over the right carotid
and the left carotid.
And typically, a patient with aortic
stenosis should have a rush of this murmur
or even a bruit sound heading into the
right carotid artery in particular.
Remember that the aorta is a direct conduit
up to the right internal carotid artery,
as opposed to having to make a quick right turn and
a left turn to get up to the left carotid artery.
So you're more likely to hear the radiating
into the carotids on the right side,
though certainly you could
hear it on both sides as well.
The last thing I'll add about aortic
stenosis is that in addition to
being able to find the stenosis or the
murmur radiating into the carotids,
because the aortic stenosis is so significant
and it's occluding the outflow tract,
it's causing blood to have a little bit more trouble
getting out into the peripheral vascular system.
As such, there's something
called 'pulsus parvus et tardis',
which is this idea that rather than the left
ventricle immediately ejecting all this blood
and being able to feel it out here to your
radial pulse, there's actually a bit of a delay.
Number one, there's a delay in the upstroke
in the carotids, so you can listen down here
at the apex.
I know that left ventricular contraction is
happening as soon as I hear the mitral valve close,
so that's the beginning of systole.
But up here, I may find that there's a little
bit of a delay between when I hear S1 occur
and when I feel the carotid
artery pulsation in my fingertips.
And that's called pulsus parvus et tardis.
The 'tardis' means late, The parvuz part simply
means that it's a little bit flat and attenuated.
The same thing applies with listening to
the heart here and simply taking the pulse.
You may find there's a delay between the apex of
the heart and the pulsation in the radial artery,
and that's called the apical radial delay, which
is one of the potential findings you may see
in advanced aortic stenosis.
All right, so the next murmur we're going
to look at is that of mitral regurgitation,
and this is an extremely common
murmur, which you will definitely hear
within the first 10 to 20 patients
you listen to on the wards.
Now, mitral regurgitation, unlike aortic stenosis,
will predictably be heard over the mitral area.
So we're going to listen best
to it down here at the apex.
The aortic and pulmonic areas are very clear right
there just to the left and right of the sternum
there at the second intercostal space.
It's very predictable, a very
discrete, specific location.
The same thing goes with the tricuspid area
down here in the left lower sternal border
at the approximately the fourth
to fifth intercostal space.
In contrast, the aortic, the mitral area
at the apex is really going to be different
depending upon the patient.
It's not going to be in exactly the same place,
you know two centimeters distal to the nipple line.
It's going to vary depending upon the patient.
So unlike finding these areas, when
you're trying to look for the mitral area,
you have to migrate around until you find
the place where your mitral valve is loudest.
So with that said, if I'm listening
for a mitral regurgitant murmur,
I'm going to be migrating around to
find the place where it's loudest.
Again, LISP, I is for intensity.
The grade of this murmur, unlike aortic
stenosis, does predict the severity
of the mitral regurgitation itself and
the extent of disease in the mitral valve,
so intensity will matter.
The shape for a classic mitral regurgitation
murmur is so-called holosystolic.
That is, it's the same from beginning to end,
and it may last for a short time in systole
or throughout systole but either way,
it should be of a constant amplitude.
So the typical onomatopoeia phrasing that we
use to describe a mitral regurgitation murmur
is also high in pitch and it goes like this:
(holosystolic mitral regurgitation sound)
You can hear that it's the exact same
amplitude, almost a square waveform in sound
from one beat to the next.
The timing again can occur
throughout systole or early or late.
Doesn't help too much with deciding that the
extent or severity of the mitral regurgitation
so much as the amplitude or intensity
or grade of the murmur would.
So let me take a listen for mitral regurgitation.
As it's high pitched, incidentally, you'll
note that I'm using the diaphragm.
And now let's say that I can sort of hear a murmur,
but I'm not 100 percent convinced that it's there,
maybe it's a 1 out of 6 murmur,
or perhaps some are worried that maybe
this is just a murmur of aortic stenosis,
which, as I said, could be all the way down there.
Fortunately, in cardiology, there are a number
of different bedside maneuvers that we can do,
which predictably will increase or decrease
the amplitude of a variety of murmurs.
And so the first one of these that we're going
to demonstrate is called the 'hand grip maneuver'.
Would you mind grabbing that towel for us.
So the hand grip maneuver is
designed to increase afterload.
So when I have him squeeze that towel
with all his might for 10 seconds,
he's going to be contracting all the
muscles in his upper extremities,
which is going to increase
peripheral vascular resistance.
That means that when his left ventricle
contracts and it's trying to forcibly eject blood
out of the aorta and out into his the
great vessels of his upper chest and neck,
there's going to be some resistance.
And so if you already have a diseased mitral
valve when that left ventricle contracts
and is trying to push blood outwards, some
of it is going to get pushed backwards
through an incompetent mitral valve.
So this maneuver, 'handgrip' is an
attempt to accentuate or exaggerate
his mitral valve murmur, his mitral
regurgitation, so let's give that a try.
Importantly, I want him to do it for 5 or 10 seconds.
Go ahead and squeeze it with all your might.
So in this case, fortunately, our patient
does not have mitral regurgitation,
but this would be the way to bring it out
if I thought that it was going to be there.
The next murmur we should talk about is tricuspid
regurgitation on the other side of the precordium.
The tricuspid regurgitation murmur has a lot
of similar features with mitral regurgitation.
It's high in pitch, It has a
(tricuspid regurgitation sound)
kind of wave form, and the grade or
intensity of the murmur that we hear
does correlate fairly well with the extent
of regurgitation in the tricuspid valve.
The location, of course, is in the
tricuspid area, which helps us out as well.
The real different feature of tricuspid regurgitation
is that since it is a right-sided murmur,
anything that affects preload that is the
blood returning to the right side of the heart
could affect the volume or loudness of that murmur.
So in this instance, what we're going
to do is a very simple observation
where when he just breathes during
inhalation, when you inspire you're creating
a negative intrathoracic pressure, you're
actually creating a small vacuum in your chest.
That vacuum is drawing blood, it actually
sucks blood from your superior vena cava,
and your inferior vena cava draws more
blood to the right side of your heart,
to your right atrium and
then to your right ventricle.
So if there's more blood in your
right ventricle when it squeezes,
more of it is going to go forward, but
also more of it's going to go backward.
So simply, this technique of paying attention
to the respiratory cycle as he quietly inspires,
quiet inspiration, we'll hopefully
find that during the respiratory cycle,
there's variability in the murmur.
So if while listening
to his tricuspid valve, I find that when
he's just casually breathing at rest,
the murmur gets louder during inhalation
and then a bit quieter during exhalation.
That feature of increased
intensity with quiet inspiration
would support a tricuspid regurgitation murmur.
Now you can imagine that if you've
got a patient who's got a fever
and potentially has a history of injection drug
use, and you're concerned about endocarditis,
simply having a typical holosystolic
murmur at the over the tricuspid region
especially if it exacerbates or is
increased in volume with quiet inspiration,
that is a very high likelihood ratio in support
of their being real tricuspid regurgitation
and we would of course, be concerned
about spontaneous bacterial endocarditis
in a patient with a history of IV drug use.